Thursday, October 22, 2009

With about 500 days left, this looks like a good time to quickly describe the plans of some notable participating teams. In some cases, information is not available, or not complete enough to warrant much discussion. But let's start with an updated list of teams. This list is probably incomplete, but represents the majority of the active teams including some that one should consider at the head of the class, Team Prometheus for example.

If your team is missing from this list, and has a web page, please comment to this post or email me (link at the upper right of the page) so that this list can be updated.

Neblua Aerospace has a very nice web page, with some images showing test equipment. While quickly browsing, I was unable to find any detailed images or plans for the rocket, however. The Cerberus rocket is planned to fly with an 8 component aerospike engine.

Epsilon Vee has planned to build a rocket called CESTUS 1, or Common Expendable Space Transportation for Ultra-small Satellites. This very small rocket is only "8 inches in diameter, roughly 12 feet long, weighing in a some 180 lbs (82 kgs). Primarily 6061 aluminum, lox / propane propellants and ablative engines. It has a payload of a whopping 1 lb (455 g)!" It is unclear if a rocket like this could ever launch payload to orbit, largely because small rockets suffer from severe low atmosphere drag and mass fraction ratios. It should be noted that this rocket has not been built yet, and the latest update here was from 2008.

SARA, the South African Rocketry Association, has some very interesting looking rocket plans. Group platform:

Aims of the South African Rocketry Association

To promote experimental research rocketry in the South Africa.To promote mathematics and science through rocketry in education.To promote space science as an industry in South AfricaTo encourage affiliation of all interested partiesTo reach the altitude of 100km, a first for a private institution in SA. The rocket on the right, which looks a bit like the NOTS-EV-1 Pilot (NOTSNIK) rocket, appears to be the N prize rocket - perhaps combined with the taller rocket next to it. Details are limited on this, and like on most pages, updates are mostly from 2008.

Micro Launchers has some solid information on their rocket plans. There is a short presentation available on very small rockets. This first rocket is called a cansat launcher, made to launch nano or pico-satellites. This rocket would certainly be the smallest satellite launcher ever used, particularly if it is launched from the ground. The high mass-fraction, high ISP bipropellant stages are a great idea. But, as usual, rockets this small suffer severe drag losses at low altitude. Most updates are several years old.

Potent Voyager has not updated their web page or posted any plans that I have found, since announcing their entry into the n prize competition on 8/8/2008. This seems to be, sadly, a common trend among these teams. What happened in 2009 that made them stop?

Team Prometheus is perhaps the most famous n prize team. They have received a large amount of press, and coverage in hobby rocketry. More importantly, this team has also regularly updated their web page, and made posts in rocketry forums. Recent developments include: Testing of a tiny satellite transmitter, a ground detection station, and a rotating launch tower. Nothing here is ready for the n prize, but these and other parts will be put to use. A rockoon launch is planned soon, and it will be one of the few amateur rockoon launches ever attempted. Here is footage from a balloon launch to near space:

And an interview:

Little Monster Rocketdoes not have specific plans, and has not updated this web page in over a year. The FAQ is detailed, however, and contains some interesting discussion. One key question is: "Is the N prize possible?" The authors say yes, comments say "show us the math."

Kiwi 2 Space has some very interesting plans and projects under development. "Our approach to the N-Prize is relatively simple. (I hope!)We plan on using a 3 stage liquid fuelled rocket to reach low earth orbit, consisting of a pump fed booster (money and time permitting or else we will resort to a pressure fed booster) and liquid fueled upper stages, from which the propellant choice is still yet to be confirmed. The rocket will be ground launched from a mobile launch platform.The 19.99g satellite will be placed in a 200km high circular orbit with an inclination of 34deg. The size of the rocket will enable us to launch multiple satellites giving us more chance of winning the prize if one is to fail. This added redundancy has been incorporated into the design so the rocket still achieves the required Delta V for orbit. For a 200km circular orbit the satellite needs a Delta V of 7786m/s to stop it dropping out of orbit, so the total rocket Delta V will be in the realms of 9300m/s."

QI Spacecraft has a simple (text only) blog that shows some progress towards a rockoon project. Images would be nice in the next post! (Sadly, the last post was from 2009.)

Aerosplice has some interesting work that revolves around a strategy of using air breathing or air augmented booster stages (pulse jet, ramjet) that do most of the heavy lifting.

"Why is the Aerosplice approach better?

Every second that a conventional rocket burns fuel, it plows through economic resources, and leaves a wake of a destroyed budget behind. Why begin acceleration as a rocket? There are so many options now to reach reasonable speeds at a cost of a thousand times less than that of conventional rockets.

To go from stationary (at rest on the launch pad) to orbital velocity (Mach 25) or even escape velocity (Mach 35) a vehicle must accelerate. Acceleration requires that you continuously burn more fuel or decrease the mass of the rocket continuously. So shouldn't that burnt fuel be as inexpensive as possible to achieve the maximum acceleration and altitude (potential energy)? Of course! Especially if that fuel is as cheap as Kerosene or nearly free in the case of hydrogen produced from sunlight and water.

Currently the conventional rocket fuels of choice are extremely expensive such as liquid Hydrogen/ Liquid Oxygen, Liquid Oxygen/ Kerosene, or Nitrogentetroxide/ Hydrazine. When using conventional rockets most of the vehicle's weight is fuel! 90%! and only a tiny percent is payload, usually between 2% and 5% . That has to Change.

What Aerosplice provides is alternative technologies to the expensive conventional routes to space. Technologies like valveless pulse jets to get the rockets off the launch pads and get them up to speeds between Mach 0.5 and Mach 0.9. Then Ramjets to get the Rockets to speeds greater than Mach 10. Then finally Hydrogen Peroxide based rocket engines to get vehicles into space and beyond. We also do extensive research into Ion, Plasma and Hydrogen Fusion systems for travel between planets and for satellite re-orientation."

Daedalus Aerospace has a Google groups page with some fairly recent updates. Balloon work is one highlight of their "recent" progress.

Team 9.99 has a great looking web page. Sadly, they do not have any further information on this web page!

Wikisat launched a test balloon in 2009, from Spain, but were unable to track or recover it according to the last update on this web page. They have a very interesting, and very tiny electronics package:

Valkyrie has some information about their plans, and updates on some very different topics, but little in the way of specific information.

has a simple web page with a statement of intent. They are a rather late entry into the N prize, so perhaps it is somewhat more reasonable that they do not have much information yet.

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It appears, in all honesty, that these N prize teams are for the most part stagnating or falling behind. There is nothing shocking or shameful in this; rocketry is hard, expensive, and for almost everyone, just a hobby. Large projects seldom wind up flying, even projects that are designed to fly a simple hobby rocket to 100,000 feet. Orbit is much harder, and the N prize is very constraining. There is little chance that any team will even attempt a credible N prize launch. Having said that, great benefits can be gained from such a competition even if it is essentially impossible. If Team Prometheus is able to do a few rockoon launches, perhaps culminating in an N-10,000 rockoon flight to space with a camera, that would have made the whole competition worthy of our time and attention.

Thursday, April 30, 2009

One can hardly improve upon the many posts and articles regarding the N-Prize, which has now been active for quite some time. We have discussed many of the possible plans and debated everything including the value of such a competition; one that is nearly impossible to complete. But all the same, there have been no substantial posts on this subject here at High Power. Below are some most relevant links, divided into general information and teams. This post will also be placed, along with any future rocketry posts not directly related to the N Prize, at the usual High Power Rocketry Page; High Power Rocketry.

The official rules are:

"The challenge posed by the N-Prize is to launch a satellite weighing between 9.99 and 19.99 grams into Earth orbit, and to track it for a minimum of nine orbits. Most importantly, though, the launch budget must be within £999.99 (about $1500) - and must include the launch vehicle, all of the required non-reuseable launch equipment hardware, and propellant."

The reward is about $15,000, but really the reward is doing something very very hard.

I would like to finish this brief discussion with my, purely hypothetical proposal to achieve the prize. Many of the above listed teams have great plans, some are traditional and others quite unconventional to say the least.

My plan:

The launch team would prepare a large helium balloon, probably an inexpensive homemade zero pressure balloon suitable for flight to or slightly above 100,000 feet altitude (near space.) -*Update, I have since noticed just how expensive helium is. Either the team may have to brew their own hydrogen, or perhaps use a solar balloon which uses plain air and can only fly to lower altitudes, but at greatly reduced prices. These solar balloons can actually be built very large for a low cost, perhaps allowing for more lift.*- Indeed if possible, 110,000 feet or 115,000 feet would greatly increase performance at little additional balloon costs. Attached to this balloon, large enough to carry approximately 100 lbs. to near space, will be a gondola package, launch tower, and rocket system. The electronics and documentation package will be maximally lightweight, on the order of 1 kg. The launch tower will also be as light as possible, made of carbon fiber or other composites (more on how to avoid the high cost of this item below), and will likely be on the order of 10 feet long. Most importantly, the rocket system will consist of an amateur O motor contained within a very light weight, minimum diameter dart airframe. This should be a high thrust O motor, an O 10,000 would be a suitable choice, or perhaps faster still. The reason for this is to achieve aerodynamic stability quickly in the thin air, which will be assisted by a 5 - 8 rps spin:

The rocket is to be fired at a 45 degree angle. At burnout, this rocket is expected to achieve a velocity of at least 5000 fps. This is, however, far short of what is required for orbit. After a short coast period, sufficient to allow the rocket to achieve an altitude of more than 50 miles, the second and final stage of the launch process will be ignited. However, as a result of the high cost of conventional rocket stages (rapidly pushing the price point over the limit), this 2nd (or perhaps 3rd) stage will consist of a shaped charge:

A powerful conic shaped charge will ignite. At the focus of this shaped charge, there will be a small metallic slug. This slug is to be lunched into orbit. This metal slug will consist of several layers, and will retain a basic useful form as in explosively shaped projectiles (see below.) Within the metal projectile, a burning thermite charge could eject chaff into orbit (for the sake of government assisted tracking), or some gas could be evolved from a filler material that will glow against the night sky and be visible from ground based telescopes. This may be compared to a tracer bullet, though it would have a full thickness of tracking material, sufficient to remain visible for 9 orbits:

This project minimizes to (according to my understanding) the lowest possible disposable cost, given a reasonable and realistic initial investment. The per launch cost, per the prize rules, would consist of the rocket propellant, shaped charge, balloon, and helium (or hydrogen). It is expected that the rocket proper and gondola and tower structure will be recovered. Having said that, it is hard to see how a small rocket launched at a 45 degree angle, into space or near space, could ever be recovered. This flaw may still not break the budget as a complete O motor and rocket could probably be built for a reasonably low cost, less than half of the total budget.

Finally, it should be noted that shaped charges seldom launch solid objects at hypersonic velocity, but in this project, nothing short of 15,000 fps is needed. This would likely be a record, and requires some really smart shaped charge design (if it is possible at all.) It may be that a 2nd or even 3rd stage would be needed to assure orbit. Also, care must be taken to avoid too much velocity, which could cause solar orbit. Perhaps using several stages could allow orbit without a shaped charge, but at what cost and complexity increases? I would welcome any comments about this plan.

This type of small object in orbit, while hardly as useful as a pico-satellite, could still allow for some limited science. The rate of decay of orbit could help refine atmospheric density measurements (as if we need more of that by now). Also, and probably most important, the tiny metal slug would allow for practice tracking very small objects. Perhaps it can help us simulate what happens to space junk after collisions and explosions in LEO, something that sadly may become more common.

Future posts may explore more about individual teams and their attempts.